Because Associated doesn't make any real money that way.
You'll be better off buying a cheap used sc10 and steal the parts off of it then but the parts new.
Chassis and side guards
battery hold down
frt and rr bumpers
body mounts
front shock tower
you can just drill the two holes needed in the rear tower yourself instead if buying a new one
tires and wheels
about 125.00 for the parts above.